Marijuana – also called weed, grass, pot, bud, ganja, Mary Jane, and a host of other slang terms – is a greenish gray blend of dried Cannabis sativa flowers. Some people smoke marijuana in hand-rolled cigarettes called knuckles, pipes, hookah bars (sometimes called bongos), or dead ends (marijuana in cigar wrappers). Cannabis can also be used to brew tea and, especially when sold or consumed for medicinal purposes, is often added to foods (edible) such as cakes, cookies, or candy. Vaporizers are also increasingly used to consume marijuana. Stronger forms of marijuana include sinsemilla (from specially grown female plants) and concentrated gums containing high doses of marijuana’s active ingredients, including hash oil, wax bud, and hard shutter. These resins are becoming increasingly popular with those who use them for both recreational and medical purposes.
The main psychoactive (mind-altering) chemical in marijuana responsible for most of the intoxicating effects people seek is delta 9 tetrahydrocannabinol (THC). The chemical is found in the resin produced by the leaves and buds, mostly of the female cannabis plant. The plant also contains over 500 other chemicals, including over 100 compounds chemically related to THC, called cannabinoids.
Marijuana use can lead to the development of a problematic use known as marijuana use disorder, which in severe cases takes the form of addiction. Recent data show that 30% of those who use marijuana may have some degree of marijuana-related disorder. People who start using marijuana before age 18 are four to seven times more likely to develop a marijuana use disorder than adults.
Marijuana use disorders are often associated with addiction, in which a person experiences withdrawal symptoms when not using the drug. People who use marijuana often report irritability, mood and sleep problems, decreased appetite, cravings, anxiety, and / or various forms of physical discomfort, which peak within the first week after quitting smoking and last up to 2 weeks. Marijuana addiction occurs when the brain adjusts to high doses of the drug by reducing production and sensitivity to its own endocannabinoid neurotransmitters.
Marijuana use disorder becomes addiction when a person cannot stop using the drug, even if it interferes with many aspects of his or her life. Estimates of the number of people who are addicted to marijuana are controversial, in part because epidemiological studies of substance use often use addiction as an indicator of addiction, even though addiction may or may not be addicted. These studies show that 9% of people who use marijuana will become addicted to it, rising to 17% among those who start using marijuana in their teens.
In 2015, about 4.0 million people in the United States met the diagnostic criteria for a marijuana use disorder, and 138,000 people volunteered for treatment for marijuana use.